Nausea is a potent stimulator of vasopressin. Nausea induced by motion sickness have shown increases in vasopressin and have shown abnormalities in the gastric myoelectrical activity. We propose to infuse vasopressin, measure its blood level and measure gastric myoelectrical activity by using the electrogastrogram in order to determine the hormone's role in nausea and gastric myoelectrical activity. This study is now closed as the investigator has left the institution.